Epilepsy is a serious and costly neurologic condition that affects approximately 3% of the US population, and is often both costly and difficult to diagnose. Presently, a physician's diagnosis is based on a combination of the physician's clinical impression, electroencephalogram (EEG), magnetic resonance imaging (MRI) and, where available, a multiday inpatient test combining closed circuit TV and EEG monitoring. Recent data have established brain inflammation as a critical factor in the pathophysiology of recurrent seizures, and we have built on this research to develop a patent-pending diagnostic blood test for recurrent seizures: CNS-specific Assay for Recurrent Paroxysmal Events (CARPE). CARPE is unique, as it measures plasma levels of sICAM5, an anti-inflammatory CNS origin protein, and TARC, a lymphocyte chemoattractor that we have found in consistently high concentrations in epilepsy patients. In pioneer data collected at the University of Pennsylvania, the CARPE blood test precisely separated patients with recurrent seizures from normal controls. [Here we will collect samples for CARPE testing from a cohort of 240 new patients at the Penn Epilepsy Center who will undergo a diagnostic workup, including an EEG. After six months of clinical care, an independent board of three epileptologists will determine each patient's diagnosis. To determine accuracy, we will construct ROC curves for CARPE's sensitivity and specificity by varying the threshold value for classifying epilepsy patients. Patients for whom the gold standard panel is unable to reach a conclusive diagnosis will be excluded from this analysis, and the area under the curve must significantly exceed 0.7. To determine the threshold values to be used in a subsequent pivotal study, we will analyze the entire group, using the gold standard panel's best estimate for patients with an unclear diagnosis. We aim to choose the threshold value of CARPE for identifying epilepsy patients with specificity of at least 0.8 and sensitivity of at least 0.8. At the conclusion of the study, we expct to demonstrate the accuracy of the CARPE test in diagnosing epilepsy and establish the diagnostic threshold values. Ultimately, we expect that patients whose CARPE test results indicate epilepsy will be able to forgo additional epilepsy diagnostic procedures.] In Phase II we will propose to validate the test in a multi-center pivotal study involving larger numbers of patients of all age groups. We expect this to lead to a successful de novo 510(k) Premarket Notification and marketing of the CARPE blood test as a rapid, widely accessible, and cost-effective diagnostic test for recurrent seizures. If successful, the CARPE diagnostic blood test will provide immediate and substantial benefits to patients and the medical community by offering a rapid, accessible, and cost-effective means of diagnosing epilepsy.